1. Field of the Invention
The present invention relates to an improvement of a camera system having a correcting image vibration function.
2. Description of the Related Art
A conventionally well-known vibration correction function in a camera system is configured such that an interchangeable lens contains a vibration sensor for detecting camera shake, and a vibration correction optical system formed of all or some of an image-taking optical system is driven in response to output from the vibration sensor.
In addition, various proposals have been made for an image vibration correction system having a vibration sensor in a camera and a correction optical system in a lens in which vibration information is transmitted from the camera to the lens through a signal line to control the vibration correction in the lens based on the transmitted data, for example in Japanese Patent Application Laid-Open No. 7-191354 (U.S. Pat. No. 6,088,533).
Such an image vibration correction system having a vibration sensor in a camera and a correction optical system in a lens as mentioned above is based on the premise that data of vibration detected by the vibration sensor in the camera or a signal for driving the correction optical system is transmitted to the lens at regular intervals. The actual working of a camera working, however, involves a number of control operations other than vibration correction, such as an autofocus operation, so that it is not necessarily possible to continue the transmission of the vibration data to the lens at regular intervals. In this event, if vibration data transmitted after some delay is used in calculations to drive the correction system, the control of the correction system which should be performed at regular intervals is delayed, and also, the resultant correction amount may be different from an amount which should actually be used for correction since the calculations of the correction amount is premised on correction performed at regular intervals.
It is an object of the present invention to provide a camera system which can prevent against deteriorated accuracy of vibration correction even when vibration data cannot be transmitted to a vibration correction unit at regular intervals.
The present invention is characterized by a camera system comprising: a camera having as a vibration detection unit which detects vibration, and a vibration correction unit which is attachable to the camera and has a vibration correction optical system which corrects image vibration and a driving control circuit which drives the vibration correction optical system based on a vibration detection signal from the vibration detection unit. The camera intermittently transmits the vibration detection signal from the vibration detection unit and time-related data to the driving control circuit, and the driving control circuit receives the vibration detection signal and the time-related data.
The present invention is also characterized in that the driving control circuit drives the vibration correction optical system based on a previously received vibration detection signal or a currently received vibration detection signal selected on the basis of the received time-related data.
The present invention is also characterized in that the time-related data is time data which represents a delay time period after a predetermined timing at which the camera should essentially transmit the vibration detection signal to the driving control circuit. The driving control circuit drives the vibration correction optical system based on the currently received vibration detection signal when the time data is equal to or smaller than a predetermined value, and drives the vibration correction optical system based on the previously received vibration detection signal when the time data is larger than the predetermined value.
The present invention is also characterized in that the vibration correction unit and the driving circuit are included in an interchangeable lens unit having an image-taking optical system.
In addition, the present invention is characterized by a camera system comprising: a camera having a vibration detection unit which detects vibration, and an interchangeable lens unit which is attachable to the camera and has a vibration correction optical system which corrects image vibration and a driving control circuit which drives the vibration correction optical system based on a vibration detection signal from the vibration detection unit. The camera intermittently transmits the vibration detection signal from the vibration detection unit and time-related data to the driving control circuit, and the driving control circuit receives the vibration detection signal and the time-related data.
Further, the present invention is characterized by a vibration correction unit attachable to a camera having a vibration detection unit which detects vibration, comprising: a vibration correction optical system which corrects image vibration; and a driving control circuit which drives the vibration correction optical system based on a vibration detection signal from the vibration detection unit. The driving control circuit receives the vibration detection signal and time-related data transmitted intermittently from the camera.
Further, the present invention is characterized by an interchangeable lens attachable to a camera having a vibration detection unit which detects vibration, comprising: a vibration correction optical system which corrects image vibration; and a driving control circuit which drives the vibration correction optical system based on a vibration detection signal from the vibration detection unit. The driving control circuit receives the vibration detection signal and time-related data transmitted intermittently from the camera.
Further, the present invention is characterized by a camera to which a vibration correction unit or an interchangeable lens can be attached. The vibration correction unit or the interchangeable lens has a vibration correction optical system which corrects image vibration and a driving control circuit which drives the vibration correction optical system. The camera comprising: a vibration detection unit which detects vibration; and a camera control circuit which intermittently transmits a vibration detection signal from the vibration detection unit and time-related data to the driving control circuit.
Additional characteristics of the present invention will be apparent from the following description with reference to the accompanying drawings.